package com.itheima.常用API.基本类型包装类;

public class Integer类 {
    public static void main(String[] args) {
        Integer i1=Integer.valueOf(123);
        Integer i2=Integer.valueOf("1234");
        Integer i4=null;
        Integer i3=100;
        int a1=i3;
        i3+=300;
        i4+=400;
        System.out.println(i3);
        System.out.println(i4);

    }
}
